Apparatus and circuit arrangement for controlling x-ray tubes



c. Nl EMAN N EIAL APPARATUS AND CIRCUIT ARRANGEMENT FOR CONTROLLING X-RAY TUBES Nov.- 25, 1941.

Filec lMay 31/1959 vvvvvvv 9 MA [A A 1L Patented Nov. 1 941 APPARATUS is azcaosr ARRANGEMENT CIRCUIT v FOR CONTROLLING X-BAY TUBES can Niemann m Kurt Bischofl, nrlanzen. Ger-- many, assignors to the'flrm Sien ens-lteiniger- Werke Aktiengesellschait, Berlin, Germany Application May 31, 1939, Serial In Germany June 25, 1938 6 Claims. (01. 250-93) The present inve'ntion relatesin general to' apparatus and circuit arrangements for" controlling X-ray tubes. More in particular, the invention relates to the control of X-ray tubes which are supplied with high tension current at both the cathode and anode; that is, both the .cathode and anode are supplied with potentials far above ground potential while the tube is in operation. Under these circumstances the switching-on and oil of the high tension current,

desirably efiected through-the medium of a grid.

controlled discharge tube, involves a considerable problem, and difficulties are introduced which it is the object of the invention to eliminate.

In accordance with the invention, a novel circuit arrangement is provided, adapted for use either in fluoroscoping or in radiographing, and so devised that the grid controlled discharge tube employed for switching purposes during radiographing is inserted at a point where its-cathode potential which is maintained on" the grid of 1 tube II by battery l1. By means of suitable circuits, including a timing switch l8, the negative potential on the grid of tube H can be replaced bya positive potential for .the desired time interval. These control arrangements for the grid of a tube such as tube II are wellknown, and as they form no part-of the invention they have been indicated only diagrammatically in the drawing. k

During the interval that the grid of tube II is at positive potential with respect to ground,

the before mentioned circuit for the X-ray tube is completed at the tube II, and high tension may be grounded. This permits of the use of known and relatively simple arrangements for.

controlling the grid of the discharge; tube.

The foregoing and other advantageous features oi the invention will be explained more in detail hereinafter, reference being made to the accompanying drawing, which is a diagrammatic with the invention. i

Referring to the drawing, the x-ray tube is indicated at I. The reference character 2 indicates a switch having position A, for radiographing and position D for fluoroscoping. Two transformers l0 and ii are shown, one of which is used in radiographing and the other in fluoroscoping, and each having a primary winding and two secondary windings on a common core. Valves or rectifiers are indicated at 5, I, and IB.' The grid controlled space discharge device,

which may be a triode of known type, is indicated atall. Two condensers are shown at S 'and 4.

The operation of the circuits during radiographing will first be described, being assumed that the switch 2 is in position A, as shown in the drawing. A suitable source of alternating current is of course .connected to the'primary winding 9 of transformer i0, and the transformer is energized. The high tension secondary windings 6 and 8 accordingly supply charging current to condensers 3 and l, respectively, through the rectiflers 5 and I. Energy may be supplied to the X-ray tube I over a circuit which includes the condensers 3 and l in series, and the tube H. This circuit is normally'open, due to a negative is x-ray tube established in the radiographing circuit drawing showing an X-ray tube and the circuits for controlling the same in accordance current is supplied to the X-ray tube from the condensers 3 and l in series. These condensers are continuously charged from the secondary windings 6 and 8 through the half wave recti fiers. r

In order to condition the apparatus for fluoro scoping the switch 2, is changed to position D. The X-ray tubel is now supplied with high tension current over a circuit which includes secondary winding l3 of transformer I 5, the valve is, the triode H, now operating as a two element valve, and the secondary winding, l2. The primary winding 14 is connected, to a source of alternating current. as indicated. Thus a symmetrical circuit arrangement is afforded, grounded at the junction of the two valves, one of which is the same tube that is 'used for switching purposes during radiographing.

The invention having been described, that which is believed to be new and for whichthe protection of Letters Patent .is desired will be pointed out in the appended claims.

I claim:

.1. A high tension circuit arrangement for an .X-ray tube, comprising two condensers con nected to the cathode and anode of the x-ray tube, respectively, means including a grid controlled discharge tube for connecting said'condensers in series, said discharge tube having its cathode grounded, and separate circuits for charging said condensers. i

. v2. A circuit arrangement as claimed inclaim 1, characterized by the provision of a transformer having twosecondary windings for charging-the I two condensers, respectively, and two rectiflers included in the two charging circuits, respectively.

. J 3. Control'apparatus for x-ray. tube, comprising a switch having radiographing and fluoroscoping positions, a high tension circuit for the position and including a grid controlled discharge tube having, its cathode grounded, means for supplying direct current to said circuit at two points separated by said discharge tube, a high tension circuit established in the fluoroscoping position or said switch and also including said discharge tube, and means for supplying alternating potentials to said second circuit.

4. In a control apparatus for an X-ray tube,

two alternative circuits for supplying high tension current to the tube, said circuits having a common section which includes a grid controlled discharge device having its cathode grounded, means for supplying direct current to one circuit at two points on opposite sides of said discharge device, means for supplying alternating voltages to the second circuit at two points on opposite sides of said discharge device, and a valve connected in the second circuit adjacent the said device with the ground connection for the cathg ode of said device between the said device and the said valve. I 5. A circuit arrangement for supplying high tension current to an X-ray tube, comprising two current supply sources connected in series with said X-ray tube, a connection between said sources. extending from the positive'pole of one source to the negative pole of the other source, a grid controlled discharge tube inserted in, the connection between said sources, and a ground connection at the cathode of said discharge tube.

6. Control apparatus for an X-ray tube, comprising two alternative circuits for supplying the tube with high tension current, means for supplying unidirectional voltages to the first of said 

